Filter and method of forming the same



June 17, 1930. E. J. SWEETLAND FILTER AND METHOD OF FORMING THE SAME 2 Sheets-Sheet 1 Filed Oct. 31, 1927 INVENTOR fignwtJJweefla/n B 6 W ATTORNEYS June 17, 1930. J SWEETLAND 1,764,660

FILTER AND METHOD OF FORMING THE SAME- Filed Oct. 51, 1927 Sheets-Sheet 2 INVENTOR EgwtJJn eetMm;

Patented Ji i -e 1?, 1930 a: J. SWEETLAND, OF HAZLFTON, PENNSYLVANIA FILTER AND EETHOD OF FORMING THE BAME Application and October 31, 1927. Serial in. 229,585.

This invention relates. to filters made of paper pulp as such, and to filters made of paper pulp after the pulp has been formed into sheets or layers in which form it may be designated as filter paper or blotting paper. The filters herein described are especially advantageous for use in internal combust1on engine oil purifying systems, where it is desirable to have a filter element that is so cheap in construction that it may be replaced in whole or in part at very small ex ense.

n resent day motor vehicles such-as automobi es, trucks and tractors, it has been found that some suitable means of clarifying the lubricating oil while the vehicle is in use is a very desirable objective to be attained from the standpoint of the cost of oil used, in improving the operation of the engine by supplying it with oil free from grit and dirt, and in the avoidance of costly repairs such as ma be brought about by the use of an oil po luted with suspended impurities. In such a system, a typical one of which is disclosed in my copending application Serial No. 677,344 filed November 27, 1923, a cloth filter element of a discardable nature has been rovided. The present invention, however, 1s designed to supply a filter element that is less expensive to discard after it has been rendered unfit for further service due to be ing clogged by impurities collected from the oil.

It is a further object of the invention to roduce an oil filter element for internal combustion engine use" that is made from paper ulp suitably formed on a central perforated ramage member.

It is a further object of the invention to provide an improve oil filter made from a paper pulp product in which certain of the first exposed areas may be removed as they become contaminated, so as to present a suitably clear surface to the oil to be filtered, after the outer layer of the paper pul prodnot has been contaminated, w1thout iscarding the entire element.-

It is a further-object of the invention to rovide a paper pulp filter for the urpose described which is made from a suitab e grade of pa er pulp, or paper pulp product, attache to a central perforated drainage tube, which is preferably enclosed in a tank or casin to receive the 'oil to be cleaned and puri ed.

It is a still further object of the invention to provide a filter for the purpose described wherein the filter element, made of pa er pulp product may be removed and discarded wit out the necessity of the operator touching the paper pulp element with his fingers.

t is a still further object of the invention to provide a renewable filter element for an automotive internal combustion engine in which the filter element is supported on a metal diaphragm which divides the filter chamber into two parts, one of which contains the filtered oil and which facilitates the removal of the filter element.

Yet another object of the invention is to provide an improved method for manufacturing filter elements for use in connection with internal combustion engines which method is attended by comparative ease of operation and low cost of manufacture.

Further objects and advantages will appear from the following detailed description of preferred forms of embodiment of the inventionas appear from the following specification and in connection with the attached drawmgs, in which:

Fig. 1 is a front elevation, artially in section and broken to illustrate t e details of the filter construction.

Fig. 2 is a central vertical sectional view of a modif ed form of filter element.

Fig. 3 is a partial view of the form of the invention shown in Fig. 2 with parts broken away to show the interior elements.

F1 4 is a sectional elevation of a modified orm of the invention embodying a filter element which automatically is loosened for uick removal when the cover is'taken oil of t e filter.

Fi 5 isa cross sectional view taken on the line 5-5 of Fig. 4.

Fi 6 is a side elevation of a drainage Y mom er used in a modification of the inven- 7 and 8..

Fig. 7 is a side elevation of the drainage member shown in Fig. 6 after it has been covered with suitable filter pa er.

Fig. 8 represents a cross sectlon taken on the line 88 of Fig. 7.

Fig. 9 shows the same element as is illustrated in Fig. 7 but having a portion of the filter paper unrolled to illustrate perfora-. tions across the roll of filter paper whereby theouter portion may be removed wlthout disturbing the remainder of the paper.

The oil purifying system now in common use on many motor vehicles and whlch 1t 1s unnecessary to illustrate here, includesas its most important active part the filter un t and the filter element included therein. This element is adapted to remove by filtration all of the impurities and objectionable accumulations from the used oils. To be 0 erative for any useful purpose, the area of t e filter element must be adequate to remove the impunties at such a rate that the lubricatin oil will be kept clear in use and will retain its lubr cating qualities. Undue size, however, is costly and objectionable because of the llmited available space on the vehicle adjacent to the motor. These principal requirements, adequate areas without undue size or excessive pressure are fundamental commercial requirements, together with the need of a removable and either discardable or otherwise renewable element to continuously, uniformly and cflicientl remove the objectionable constituents of t e used lubricating oil.

Referring especially to Fig. 1 the used lubricating oil 1s conveyed by means of the conduit .10 from the crank case (not shown), which is the usual engine reservoir, to a suitable form of casing or container 12, which is supported by any suitable means in a desirable location adjacent to the motor from which the lubricating oil is desired to be clarified.

The reservoir or filter tank 12 is provided with an enclosing cover or cap 14 and a gasket 16 inserted in the face thereof to correspond to and cooperate with the outwardl flanged edge 12" of the container 12. A re nforcing ring or annulus 18 is provided under the flanged edge 12* to reinforce the edge and receive the ends of the yoke 19, which by means of the screw 20 will tightly fasten the cap 14 to the container 12 in a substantially sealed condition so that the oil under pressure within the casing 12 may not escape.

The cover. portion 14 is provided with a centrally located verticalbore 21 which communicates with a transverse bore 22 running through the top. This vertical bore 21 is threaded to receive the filter element 24 so that the oil'which passes through the filter element 24 will rise upwardly by virtue of the pressure within the casing, and discharge through the bore 22 into a suitable line of tubing which conveys the filtered oil back to weight an the crank case of the engine, or to any suitable place within the interior of the engine so that the filtered oil will find its way back into the general circulation.

While the filter element emplo ed in this invention may be used in any suita 1e form or container, in automotive engineering it is desirable to rovide a container that is light in d quickly opened for cleaning or replacing the filter element. Such a container is illustrated in Fig. 1,the special construction of which, due to the flange 12 and the reinforcing ring 18, makes it possible to use a casing made of very thin sheet metal or ordinary tin plate, and the expense of a plurality of screws or bolts ordinarily employed for sealing pressure tight containers is entirely avoided in this construction.

The rectangular element shown in Figs. 2 and 3 may be employed in the same type of container as illustrated in'Fig. 1; or the same principles of construction may be employed and a rectangular tank used if desired.

The construction of the filter element 24, which, together with its use comprises an important feature of this invention, is formed as follows:

The paper pulp selected for use, which may be sulphlte pulp, soda pulp',-so called mechanical paper pulp, or any desired mixture of these substances, is first softened and beaten into a homogeneous mixture with water. The drainage element 26 is connected with a suitable source of suction and the perforated element is submerged in the mixture. The suction immediately starts to draw the water through the drainage element 26 and filtration of the pulp mixture which is thus brought about causes the aper pulp to deposit rapidly upon the rainage element, quickly building up a body of pulp in approximately the orm herein illustrated. When the element has acquired the desired size it is withdrawn from the fluid mixture and as suction continues through the drainage element the surplus water is ra idly drained from the mass of pulp and its brous nature causes it to adhere to the perforated element as shown in the drawing. The element is then thoroughly dried and is ready for use. It will be noted that the drainage element 26 is larger throu hout most of its perforated portion thant e u per ortion or stem. This, coupled with the act t at the stem is purposely perforated in such a manner as to leave'sharp irregular burrs around the perforations, causes the element to stick to the drainage member throughout all conditions pertaining to ordinary use.

For certain requirements I prefer to form the filter element 24 with different grades of pulp so that they will form in concentric layers about-the filter element. For instance I may provide three successive tanks containing mixtures of pulp and water suitably kept in a state of agitation. The. first tank may contain a long fibre kraft paper pulp, and a thin layer of this material is first deposited so as to insure a layer of lon fibre material that will not pass through t e perforations of the drainage tube. After this is deposited, the element still under suction is submerged in a mixture of soda pulp and mechanical pulp which forms a very fine grained deposit to prevent the most minute particles in the oil passing through. This layer may be made still finer by mixing kieselguhr with the pulp if desired. The outer layer may be of soda pulp, or a mixture of soda pulp and kraft pulp to give a comparatively coarse texture to the outer layer of the element. The result of these operations, which are followed by the usual draining. and drying process described above is to supply an element of graduated density, which in use allows some of the suspended solids from the oil to penetrate the surface of the element t) a certain extent, and thus clogging of the element does not occur as soon as though a line grade of pulp were used throughout for in the latter case the fine texture causes a bed of slime to form on the superficial area of the element at once and thus retard the rate of flow.

From the foregoing it will be noted that by the process described of mixing various grades of paper pulp or mixing other sub-. stances, such as kieselguhr, with them, or of depositing various grades of paper pulp in successive layers,a filter element of varying or graduated density may be formed to meet theparticular requirements in hand. Four or five grades of pulp may be deposited if desired, the first being coarse to mat over the perforations, then a layer of fine followed by several successive layers each a little coarser than the last This order may be reversed or varied as desired to meet special requirements. If it is desired to prevent pene-- tration of the solids into the element to facilitate cleaning the surface, then the fine pressure, and to expand again when the pressure is released,.as by stopping the engine upon which the filter is installed. The effect of this expansion is to loosen the slime bed and to cause at least a portion of it to fall off and settle to the bottom of the container, thus partially cleaning the filter element automatically, so that when the engine is again started the rate of flow is more rapid than would be the case if all or a part of the adhering slime had not been discharged.

A sl'ghtly modified form of the invention contemplates the use of a series of layers of built a fine screen 31 and on this, a series of layers of blotting paper 32, 33, and 34. In such an arrangement,'the outer sheet or layer of blotting paper is adapted to be removed as it becomes fouled and no longer fit for service. The remaining layers act as a supplemental filter for catching any minute particles that escape the outer layers or coverings. However, as they in turn become fouled, they Will be removed and replaced. The paper pulp blotters are particularly well adapted for such filtration and are economical in use and inexpensive to replace.

In the filter illustrated in Fig. 4 any of the types of'filter element herein described may be employed, but for illustrative purposes have represented a filter wherein the filter element 36 consists of-a cylindrical body of paper pulp formed about the perforated drainage member 37, which has a metallic supporting disc 38 attached to the bottom thereof to prevent the element sagging in the event that it becomes softened by heat and moisture under working conditions. The upper portion of the drainage member at point 38 is slightly expanded, and at 39 it is flanged outwardly so that in effect it is riveted to the metal plate 40, solder being employed around the flange 39 to seal the joint 1f necessary. A wire loop or handle 41 is preferably soldered to the plate 40 to supply a convenient means of lifting the plate and its attendant filter element out of the filter casing 42. The casing 42 is supplied with a flange 43 which is recessed at point 44 to exactly the thickness of the plate 40, which is of such diameter as to fit'loosely into the recess 44. An annular gasket of cork or other suitable material 45 forms a joint between the flange 43, the plate 40, and the cover 46, the cover 46 being tightly held in position by the yoke 47 and the tightening screws 48. From this construction it will be seen that the plate 40 forms a diaphragm which completely seals and separates the space 49 from the space Within the casing, permitting communication between the two spaces only through the filter element 36. A threaded opening 50 is provided with a tubular connection, not shown, which leads the filtered oil back to the crank case of the engine. In op eration, a branch line from the oil circulating pump of the engine discharges oil through the tube 51 into the casing 42, forming a pressure within said casing. The pressure forces the oil through the element 36 upwardly through the drainage. tube 37 into the space 49, out of which it discharges through the opening 50 to return ,to the crank case. The drain plug 52 is used for drawing off accumulated impurities that may settle within the casing Y Froin the above description of the device illustrated in Fig. 4 it will be noted that 3 when it is desired to remove the element 36 for cleaning or for replacement by a new element it is only necessary to loosen the screw 48, remove the yoke 47 and cover 46 when the filter element may be lifted out by means of the 'wire loop or handle 41 without the necessityof the operator soiling his hands.

In this connection it is pointed out that the filter elements used in the treatment of automotive crank case oil acquire athick coatin of black carbonaceous slime which make the elements very disagreeable to handle, and there is, therefore, a marked advantage in the construction illustrated in Fig. 4. which provides an element that can be lifted out of the container without the necessity of loosening screws or other mechanical attachments between the filter element and the other parts of the filter construction.

The cross sectional view.shown in Fig. 5 shows the position of the cylindrical filter element within the casing. In the modification shown in Figs. 6, 7, 8, and 9 the filter element is shown adapted to a casing such as is illustrated in Fig. 1, but it is obvious that by slight modification such an element may be attached to a circular plate as shown at 40 in Fig. 4 and thus be adapted to that type of filter casing.

Referring particularly to Fig. 6, 53 is a perforated drainage tube having discs 57 and 58 attached to it in such manner as to form a spool terminating at one end in a threaded nipple 59.

Fig. 7 represents the drainage element shown in Fig. 6 after it has been spirally wrapped with blotting paper or other type of filter paper suited to the purpose and 1s further shown in cross section in Fig. 8. This filter paper 60 is provided with rows of perforations as shown at 61 in Fig. 9, and these perforations are so spaced that each sheet formed between the perforations will at least be equal-to the maximum circumference of the finished roll. On the left hand side of each row ofperforations (Fig. 9) a strip of cement 62 is provided and when the paper is rolled on the spool or drainage member each strip of cement fastens the paper to the underlying layer at that point. The result of this construction is that as the filter element is used and the outer layer becomes clogged with solids filtered from the oil the end of the roll may be detached and the paper unrolled until the point of attachment caused by the cement 62 is encountered. The outer sheet is then easily torn off by reason-of the perforations, and is discarded, leaving the outer surface of the roll substantially clean for further use. Then the remainder of the element is put back into the filter and used .pulp or other fibrous filter material which may be used in conjunction with a central drainage member which the filter pulp or paper encloses, to permit oil from an internal combustion engine which has become contaminated in use to be forced through the;

pulp or paper to be purified and clarified by removal of the impurities therein. The filter g element is of an inexpensive material that may either be formed by vacuum on the drainage tube or may be in the form of sheets of blotting paper of such a character that they will absorb the impurities in a fashion similar to that of the formed paper pulp. The blotting paper may all be of the same quality or it may vary in texture to give any desired amount of resistance to oil flow. The

sheets are adapted to be individually or (301- lectively removed as they become contaminated and the expense or labor involved in replacement is extremely small and practically negligible as compared to the advansure.

The area of such a unit is ample to clarify the oil while in actual use and will remove the impurities at a rate equal to or greater than any rate at which they can form. By starting with clean oil and a similar fresh filter unit, observations will indicate the efficient limit of the use of the filter element and with the minimum of cost and labor and time, the element may be changed and with a new element in place, the oil will be continually kept in a highly desirable lubricating condition.

It is to be understood that the term paper pulp means includes that form of pulp made out of wood or rags or pa er that has a fibrous nature and the term fi er pulp means any pulp of fiber suchas paper pulp fiber, asbestos fiber or similar materials.

While I have illustrated forms of embodiment to which the invention is adapted, I am aware that other modifications may be de-' vised and I, therefore, desire protection on and drawing said pul v drainage then submerging the creating difference member and its its main support, which comprises submerg-' ing said drainage member in a solution of soda pulp and drawing said ulp on by in pressure etween the outer and inner surfaces thereof, then submerging'the drainage, member and its preliminary coatin in a second solution of soda pulp, asbestos fiber and kieselguhr with the vacuum a plied, and thensubmerging the artially ormed filter element in a solution of long fiber kraft paper pulp and also drawing on the final coat by means of the vacuum and finally permitting the element to dry and mat the fibers of the various layers to rovidea substantially unitary fiber pulp filter element. v

2. The method of making a fiber pulp filter element for lubricating oil systems which has a perforated drainage member for its main support which comprises, submer ing said member in a solution 0 pulp of comparatively fine texture and drawing said pulp on said member b means of a vacuum, rainage member and its temporary coating in a second solution of pulp of less fine texture and drawing on a second coating by means of a vacuum, and finally permitting the element to dry to provide a substantially unitary fiber pulp filter element.

3; The method of making a fiber pulp filter element for lubricating oil system which has a perforated drainage for its main sup ort which comprises, submerging said dralnage member in a solution of comparatively coarse ulp and forcing said pulp on said member loy means of a differential of pressure, then submerging the drainage reliminary coatin second solution of relatively fine pu and apply the differential of pressure an then submerge the partially formed filter element in a solution of less fine pulp and drawing on the final coating by means of a differential of pressure and finally permitting the element to dry to provide a substantially unitary fiber pulp filter element.

4. The method of making a fiber pulp filter element for lubricating oil systems which has a perforated drainage member for its main support which comprises submerging. said dramage member in a solution of long fiber paper pulp and drawing a thin layer of said pul on said member by means of a vapuum, the submerging the drainage member and its second solution 0 pulp of very-fine texture means of a vacuum, drainage member in a solution of pulp of comparatively coarse texture and applying the vacuum and finally drying the member,

with its coats of pulp by means of a vacuum.

5. The method ,of lmaking' a fiber pulp filter element for lubricating oil system reliminary coating in a on the member by t en submerging said which has a perforated drainage member for its main support which comprises submerging said drainage member in a solution of long fiber paper pulp and drawing a thin layer of said pulp on said member by means of a vacuu1n,then submerging the drainage member and its preliminary coating in a second solution of pulp of very fine texture mixed with 'kieselguhr and drawing said pulp on the member by means of a vacuum, then submerging said drainage member in a. solution of pulp of comparatively coarse texture and finally drying the member with its coats of pulp by meansof a vacuum.

6. In an internal combustion engine an oil pumping system of the class described, a filter element comprising a central drainage portion having a layer of relatively coarse filter pulp adjacent thereto, a layer of pulp of very fine texture surrounding said first mentioned layer and a layer of less fine texture surrounding last mentioned layer.

7. In an internal combustion engine, an oil pumping system of the class described, a filter element comprising a central drainage portion, a layer of long fiber paper pulp immediately surrounding said draina e portion, a second layer of pulp of very ne texture mixed with kieselguhr surrounding said first mentioned layer and an outer layer of comparatively coarse texture pulp surrounding said last mentioned layer.

In-testimony whereof I have affixed my signature to this specification.

ERNEST J. SWEETLAND.

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